Breeding Wheat to Endure Stress

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Wheat breeders are working on a number of fronts to help make wheat a more resilient crop when it comes to heat and water stress.

During the past several years, wheat has received increased investments from the private sector, universities and non-governmental organizations. There’s a feeling that the industry that is on the cusp of taking wheat to that next level, says Jon Rich, a Syngenta Central Plains wheat breeder and product manager in Junction City, Kansas.

Today, there are 39 active public wheat breeding programs in 27 states. The U.S. Department of Agriculture Agricultural Research Service funds two cultivar development programs and several support and germplasm enhancement programs. Plus, Syngenta, DuPont, Limagrain, Bayer CropScience, KWS and Dow AgroSciences all have wheat breeding programs.

One characteristic that seems to be getting a great deal of attention is breeding wheat so that it can better tolerate water-stressed environments. At Syngenta, Rich says they are working to improve drought tolerance and water use efficiency of wheat. “With wheat, you don’t just need to worry about water, but heat, too,” he says. “Because it’s a cool-season grass, it prefers cooler temperatures. We need varieties that can respond to severe drought situations and general reduced water.”

A wheat plant’s productivity falls off dramatically when temperatures rise above 82 degrees Fahrenheit and the effects are particularly dramatic in the flowering stage when the plant sets the seed that is ultimately harvested and milled for food. Every rise of just a couple of degrees above 82 in the flowering stages cuts yields by 3 percent to 4 percent, explains Kulvinder Gill, who holds the Vogel Chair for Wheat Breeding and Genetics at Washington State University.

Researchers at Washington State University are working to develop wheat varieties that grow under severe drought conditions, known as “desert wheat.” Their efforts earned them a $1.6-million grant in 2010 from the National Science Foundation and the Bill & Melinda Gates Foundation. Led by Gill, the team is focused on developing alternate gene systems to reduce plant height in wheat and other cereals. Last year, it was announced that Gill’s team would lead a $16.2-million international effort, funded by the U.S. Agency for International Development in partnership with the Indian Council of Agricultural Research and Directorate of Wheat Research, to continue work in this area. Researchers aim to have their first set of “climate-resilient” wheat varieties in four years.

“We are facing the twin challenges of how to increase intrinsic yield and adapt current wheat varieties to cope with these environmental challenges,” says Steve Patterson, Bayer CropScience’s global crop manager for cereals. Some climate models even show that a temperature rise of two degrees by 2050 will lower wheat yields by an average of 20 percent.

“Everyone in the wheat sector is trying to move new and improved products faster to the consumer,” says Rich. Because of the increased resources being invested into wheat, Rich says that the functionality of markers has come a long way. “We can sort through the bad stuff much faster, and the faster we can sort through the bad stuff and get to the good stuff, the faster and more efficient we are,” he says, noting that the use of double-haploids helps to decrease the time it takes to get to the marketplace.

Marker-assisted breeding and double-haploid technology work together. “We use both to produce more double-haploids and increase efficiency with the markers,” he says.

Wheat is very complex, but it’s also very efficient and can buffer itself wherever it’s grown around the world. “It’s known as a tough crop,” says Rich, who has essentially grown up in the wheat breeding industry. His father is a wheat breeder and Rich used to spend hours a day with him as a kid looking at wheat. Rich says that today, the industry needs to push yield potential and take it to the next level.

He says one of the benefits of working for Syngenta is its worldwide cereals and wheat breeding program. “I can access germplasm from anywhere, which helps to enhance our local germplasm base — that’s a huge benefit,” he says. “I get to look at wheat all over the world, bring some back to Kansas and make crosses that could bring promise to producers in the Plains.”

Rich adds that the most important thing for any wheat breeding program is still the combine — cutting plots to see how a line performs. “The more test plots we can harvest and collect data from, the better,” he says. “The more numbers you run, the more likely you are to find the ones that will take you to that next level.”

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Every rise of just a couple of degrees above 82 in the flowering stages cuts yields by 3% to 4%

Breeding Local
In sifting through the data, breeders such as Rich are looking at straw strength, maturity, disease and viruses, and maintaining or improving milling and backing quality.

In every region, wheat breeders are looking to achieve something different. Rich, whose region comprises 16 million acres of wheat, is focused on maximizing yields. “We’re really looking for top-end yield potential that can be grown in dry land and irrigation,” he says. “We take growth performance, straw strength, yield and tolerance to fusarium head blight into account.”

Wheat breeders would like to see wheat as a rotation alternative to help alleviate weed resistance and manage farm risks. “As you move east of Interstate 35, you don’t see much wheat because of the economics of corn and soybeans,” Rich says, noting that all varieties are susceptible to fusarium head blight.

The winter wheat varieties don’t have a high level of resistance. Fusarium thrives in humid and wet conditions. Rich says that every wheat variety has an Achilles heel of some kind. “At Syngenta, we look at how we can negate that Achilles heel either with seed treatments, planting dates or agronomic practices,” he says. “If the Achilles heel is too big, the variety never makes it to the market.

“We strive to give producers the highest-yielding varieties with the recipe to achieve that. All our lines are thoroughly tested across many locations in eight states from North Dakota to Texas. We are testing for winter hardiness, to identify any attributes that might be either beneficial or detrimental to farmers.”

Hybrid on the Horizon
Rich couldn’t speak specifically to Syngenta’s work with hybrid wheat, but he says the future is bright. Based on the company’s experience with hybrid barley in Europe, Syngenta is confident it can make hybrid wheat varieties available to growers in key markets within a decade.

While primarily focused on advancing corn and soybean genetics, as well as canola and rice, DuPont Pioneer announced that it has added hybrid wheat technology to its roster of crop research programs. “We’re leveraging our expertise in wheat breeding and hybrid seed production to develop a new generation of hybrid wheat,” says John Soper, DuPont Pioneer vice president of crop genetics/research and development. “These advancements will bring about new yield potential for wheat farmers.” The company is at least a decade away from commercializing its new wheat. Researchers have identified the genes they want and are now starting to make transformations and figure out which combinations work best, Soper says.

“At the end of the day, we are all trying to give farmers the best yields,” Rich says.

Julie Deering

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